Impregnated and coated fuel body and method



IMPREGNATED AND COATED FUEL BODY AND METHOD George 'B. Powell, Daytona Beach, Fla, assignor to Tamwell Enterprises, Kansas City, Mo., a company Nbnmwing. Application April 1t, 1955', SerialNo. 500,645 5 Claims. (-21. 44-6) This-inventionrelates to "a fuelbody, and more particularly to an economical, coated and impregnated charcoal fuel body.

Theuse'of charcoal as a fuel for cooking food has gained .grea'tpopularity in recent years, both forindoor andoutdoor facilities. This-can'be attributed to a substantial lowering of the cost, the convenient 'forms now available and "the improvement-in the taste 'of food by charcoal broilingi The'most serious drawback totheuse of charcoal as a source of heat in broiling foodon a grill is the init-ial difficultyencountered in getting'thecharcoal to burn. The kindling point of charcoal being higher than the temperature produced by an ordinary match, some method suchas saturating or pouring on a highly flammable fuel before igniting with the match has been necessary. -l n the-alternative afire'of some easily ignitible material'may be started and then the charcoal added,--the cooking being held up until the first materialhas completely burned away because of the smoke and odor produced. Thisinconvenientand laborious processhas been a deterrent to many persons who otherwise would avail themselves (if the advantages of charc'oal broiling. 'Having- 'r'egard-to these problems-"arid difficulties, it-is pri-rnaryobject of-the-presentinvention to provide an easily ignitable fuel body that produces an intense heat. An equally important objcftheprovision of a fuel body that is-subStantialIy free of obnoxious s'itibke' and odor while burning.

A further object is the provision of a fuel body that has been impregnated with a liquid hydrocarbon and then coated with a relatively impervious, flammable, organic polymerized material that when dry renders the fuel perfectly clean to handle.

Another object is to provide an easily ignitible fuel body that because of the ease and rapidity of manufacture, and the low cost of the materials, may be made available at a reasonably low cost.

With these obects in view the process of producing the fuel body may best be demonstrated by the method hereinafter more fully set forth.

The fuel body of the present invention is produced by first immersing a charcoal briquette in odorless mineral spirits for approximately one to two seconds. After withdrawing the briquette and holding for 30 seconds above the liquid hydrocarbon tank it is immersed in a tank of flammable coating material for approximately one second. When withdrawn from the tank the briquette is allowed to stand over the tank until the excess material has dropped 01f, then it is placed on a flat surface, such as glass, steel or other like smooth surface. At the end of about three minutes, it is turned over and placed on another like surface. When thoroughly dry it is removed and is ready for packaging.

Although many porous combustible materials could be utilized in the present fuel body, charcoal, a product of the destructive distillation of coal or wood, has the desired Characteristic of producing an intense heat with substantae atent 2,816,0l3 Patented Dec. 10, 1957 tially no smoke. For cooking purposes wood charcoal is preferred, while for other purposes, coal charcoal would be equally satisfactory. The size and shape of the fuel body is determined by the particular need. Charcoal pressed and molded into a self-sustaining briquette is the best form for cooking. Many uses for the present in vention are obvious, however, and therefore the particular need would dictate the size and form of the fuel body. Larger pieces, for instance, would be needed for use in starting'fires in fireplaces and other similar uses.

A'ny liquid hydrocarbon of sufficient volatility could be used in the present invention to impregnate the fuel body, but a mixture ofsubstantially pure liquid alkanes gives the preferredresults as the absence of appreciable amounts of aromatics results in substantially no smoke being produced during the burning. These alkanes are commercially available and are usually known by the name odorless mineral spirits.

Some important factors must be taken into account in determining th'e'rnost satisfactory mixture to be used. It has been found that the higher the boiling point, the longer the evaporation rate, and the lower the kauri butanol number, the longer the alkane compositions are confined in the charcoal body. The specific gravity of the liquid alkanes must not be too high as excessive white smoke may result during the burning. Aromatic and unsaturated hydrocarbons are not as easily confined within the interstices of the charcoal and also have the objectionable tendency to create odor and smoke when burned. An example of a-suitable alkane mixture is the following:

Distillation ran e, 0.:

Kauri butanol numberttt Flash paint, C 809 Evaporation ra'te (minutes) 1 07 The practical limit of the boiling point would be-approximately 300* centigrade and the minimum would of secessit'ybeno'lewer than 25 Centigrade.

It has been found that various organic polymerized materials are suitable as the coating material for the present fuel body. Many polymers could be utilized, but they preferably should have the following characteristics; melting point within the range of 25 C. to 300 C., flammable, relatively impervious to the liquid hydrocarbon fraction, and produce very little smoke or odor during burning.

The acrylic ester resins are the preferred polymers, especially methyl acrylate, ethyl acrylate, propyl acrylate. Also utilizable are methyl methacrylate, ethyl methacrylate, propyl methacrylate, methyl ethacrylate, ethyl ethacrylate, propyl ethacrylate, methyl propacrylate, ethyl propa-crylate, and propyl propacrylate. Mixtures of the above, as well as copolymers may also be used successfully. Other types of polymers that can be employed in the present process include the nitro celluloses, and the ethyl celluloses which effect the desired result of retaining the liquid hydrocarbon Within the fuel body.

In order to render the polyacrylate coating materials more flammable, cellulose nitrates may be added. The nitrogen content of the cellulose nitrates should ideally be over 12%. A coating material containing 40%50% cellulose nitrate in which the nitrogen content is 13.41% is the most suitable material, and produces a coating that is rapidly flammable and presents no safety hazards.

The coating material is dissolved in a suitable organic solvent so that it may easily be applied to the fuel body. In order to assure a monolithic coating without bubbles, it is best to use a solvent that does not evaporate too rap- Acetone Toluene; ml 25 Polyethyl acrylate gms 10.0 Cellulose nitrate (13.41% nitrogen) gms 7.54

When dipped in the alkane composition the fuel body absorbs a sufiicient quantity of the liquid hydrocarbon composition during this interval so that it will burn for a period long enough to ignite the fuel body. The flame from the burning of the hydrocarbon composition and coating material lasts for a time sufiicient to ignite the fuel body which becomes a glowing coal. If the fuel body is to be used to ignite other material, such as wood in a fireplace, its immersion time in the liquid hydrocarbon may be increased, depending on the particular use anticipated. The increase in absorbed hydrocarbon composition will result in a larger and longer lasting flame.

The fuel body, after being impregnated with the liquid hydrocarbon, is held over the tank for approximately 30 seconds before being dipped in the coating material. This is to allow the greater part of the air within it to escape, as the air would cause bubbles in the surface of the coating material. Also the coating should be allowed to dry on the fuel body at about 20 C. More than one coat of the organic polymerized material may be applied to the fuel body, and to do this it is best to allow suflicient time between the application of each coat as above set down and then proceed as if only one coat had been applied as previously described. I

Having thus described the invention what is claimed as new and desired to be secured by Letters Patent is:

1. An easily ignitible fuel body comprising a self-sustaining body of highly porous charcoal, impregnated with a saturated aliphatic hydrocarbon composition consisting of liquid alkanes substantially free of unsaturated and cyclic hydrocarbons, said composition having a distillation range between 25 and 300 centigrade, and a relatively impervious, flammable, polymerized coating around the body of suflicient thickness to retain said composition within the body for an extended period of time, said coating being selected from the group consisting of acrylic ester resins, nitro celluloses and ethyl celluloses, and having a melting point within the range of 25 to 300 centigrade.

2. A fuel body as set forth in claim 1 wherein the distillation range of said composition is within the range of approximately 210 to 240 centigrade, the kauri butanol number of the same is approximately 23 and the evaporation rate thereof is approximately 100 minutes.

3. The process of producing an easily ignitible fuel which comprises the steps of immersing a self-sustaining, highly porous body of charcoal in a saturated aliphatic hydrocarbon composition consisting of liquid alkanes substantially free of unsaturated and cyclic hydrocarbons, said composition having a distillation range between 25 and 300 centigrade, for a time suflicient to impregnate the body with the composition; and subsequently coating the body with a relatively impervious, flammable, polymerized material of suflicient thickness to retain said composition within the body for an extended period of time, said material being selected from the group consisting of acrylic ester resins, nitro celluloses and ethyl celluloses, and having a melting point within the range of 25 to 300 centigrade.

4. A process as set forth in claim 3 wherein said polymerized material includes cellulose nitrate containing approximately 13.41% nitrogen.

5. A process as set forth in claim 3 wherein said coating is formed on the body by dipping the latter into a solution containing cellulose nitrate (13.41% N) and polyethyl acrylate dissolved in an admixture of acetone and toluene.

References Cited in the file of this patent UNITED STATES PATENTS 2,120,206 Nelson June 7, 1938 2,604,389 Berdick July 22, 1952 FOREIGN PATENTS 477,770 Canada Oct. 16, 1951 

1. AN EASILY IGNITIBLE FUEL BODY COMPRISING A SELF-SUS TAINING BODY OF HIGHLY POROUS CHARCOAL, IMPREGNATED WITH A SATURATED ALIPHATIC HYDROCARNON COMPOSITION CONSISTING OF LIQUID ALKANES SUBSTANTIALLY FREE OF UNSATURATED AND CYCLIC HYDROCARBONS, SAID COMPOSITION HAVING A DISTILLA TION RANGE BERTWEEN 25* AND 300* C, AND A RELATIVELY UMPERVIOUS, FLAMMABLE, POLYMERIZED COATING AROUND THE BODY OF SUFFICIENT THICKNESS TO RETAIN SAID COMPOSITION WITHIN THE BODY FOR AN EXTENDED PERIOD OF TIME, SAID COATING BEING SELECTED FROM THE GROUP CONSISTING OF ACRYLIC ESTER RESINS, NITRO CELLULOSES AND ETHYL CELLULOSES, AND HAVING A MELTING POINT WITHIN THE RANGE OF 25* TO 300% CENTIGRADE. 